Polymers prepared by the polymerization of relatively simple, ethylenically-unsaturated monomers such as (meth)acrylic acid and its esters, (meth)acrylamide, maleic anhydride or maleic acid, crotonic acid and its esters, methyl vinyl ether, vinyl acetate, acrylonitrile, styrene and the like, are well known and are relatively easy to prepare by polymerization techniques well known in the art. The preparation of polymers that contain hydrophobic pendant groups by the polymerization of ethylenically-unsaturated monomers which contain such hydrophobic groups using conventional polymerization techniques is limited by the availability of such monomers and possible complications arising in the attempt to incorporate such monomers into the polymer during the polymerization. Complications during the polymerization may well occur if the hydrophobe-containing monomer does not have solubility characteristics that are compatible with the desired polymerization technique(s).
The difficulties generally encountered in the synthesis of polymers which contain pendant hydrophobic groups by conventional polymerization techniques for ethylenically-unsaturated monomers are generally multiplied if the desired goal is to prepare a polymer which also contains pendant alkoxylated groups. The monomer availability problems, and complications in incorporating such diverse monomers into a polymer, are severely increased.
Post-polymerization derivatization of polymers prepared by conventional polymerization techniques, using relatively simple and readily available monomers, whereby pendant hydrophobic groups, or a mixture of pendant hydrophobic groups and pendant alkoxylated groups, are introduced into the polymer avoids the difficulties regarding monomer availability and the complications encountered in incorporating such unusual monomers during a polymerization reaction. Such a post-polymerization process is highly desirable if it is economically efficient. Economic efficiency is dependent upon many variables, including the efficiency with which the process proceeds, the reasonableness of the reaction conditions required, the availability of both the basic polymer(s) to be derivatized and the derivatizing agent(s), the use of a minimum of reaction steps, the ease at which the end product polymer can be recovered from the reaction mixture, and the like.
Polymers having unique mixtures of pendant hydrophobic groups and pendant alkoxylated groups are highly desirable given the unique properties imparted to the polymer by the combinations of such diverse groups.
It is an object of the present invention to provide a process for preparing a polymer containing pendant hydrophobic groups and both pendant hydrophobic groups and pendant alkoxylated groups by post-polymerization derivatization using polymers prepared by conventional techniques using readily available monomers. It is an object of the present invention to provide such a process whereby such groups can be incorporated into a wide variety of pre-existing commercially available polymers. It is an object of the present invention to provide such a process that minimizes the reaction steps required and the time required for the derivatization. It is an object to provide such a process that proceeds under relatively mild reaction conditions and minimizes any deletorious effects on the polymer structure. It is an object of the present invention to provide such a process that generally can employ commercially available derivatizing agents. It is an object to provide such a process that employs generally a reasonably high concentration of reactants, and hence renders the method economically desirable as to the end product yield for the given time, equipment, energy and the like utilized. It is an object to provide such a process wherein the polymer end product is easily recovered from the reaction mixture.
It is an object of the present invention to provide a unique polymer having incorporated thereinto mixtures of hydrophobic and alkoxylated pendant groups.
These and other objects of the present invention are described in more detail below.